Abstract:
After filling, paste reaches its heyday with the paste wall capable of repeatedly withstanding the fracture pressure of goaf roof. The strength of paste wall should be no less than the roof weighting. In order to identify the dynamic coordination mechanism of filling wall strength and roof pressure, the movement principle of goaf roofs was studied in detail. The weighting characteristics of roofs at different stages were differentiated, with the weighting pressure of specific roof strata structure also obtained. Requirements for the mechanical properties of paste filling wall at different stages of its strength-developing period was also proposed. Paste materials that meet the dynamic coordination requirements were formed based on the experiments for aggregate size and ingredients ratio and consist of crushed stone, sand, cement, coal ash, additive and water. An industrial test was carried out, and the actual effect of paste wall proves the rationality of research results.